OK. I just spoke to my father who happened to be standing around with a bunch of other guys in Corbin. They all agreed that poke sallet cooked alone wasn't "nothing special" And that it was usually mixed with mustard or some other greens.
They also said that it was definitely best when picked young. However, none of them thought that it would cause any harm if eaten after the berries. They said that it just wasn't as good. I think they may have said it was "more tough"
Apparently, I've also been signed up for a lesson from my father in finding and picking poke sallet come this Spring...and once I have some, I'll try to remember to donate to the forum. Dad confirmed "it pretty much grows everywhere. It's a weed."